Help with custom STC15W204S (8051) MCU package / Pin activation and bus errors

#1 · October 4, 2026, 2:54 am

Hi, I am currently working on creating a custom package for the STC15W204S (SOP8) microcontroller, which is based on the 8051 architecture. So far, I have achieved the following:

The microcontroller now appears in the i51 list. I placed an i51.xml file at the same directory level as my STC15W204S folder in my user directory.
The MCU can be selected from the menu and renders properly on the circuit canvas.

However, I am facing two specific issues that I haven't been able to resolve, and I would really appreciate your guidance:

Inactive I/O Pins: The pins are rendered, but they remain inactive, meaning I cannot connect wires or link them to other components. I suspect this is related to the type attribute in the pin definitions, but I couldn't find detailed documentation about it. What is the correct way to configure them for bidirectional I/O?
Serial Console Errors: When the component initializes, the serial console displays the following errors: see stc15w204s.png

Uploaded files:

STC15W204S_package.zip

#2 · October 4, 2026, 8:31 am

Hi.

I think both problems are related to unused pins.
To solve this edit package file and use: type="" instead of type="nc"

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